Gas turbine engines are used to power aircraft, watercraft, power generators, and the like. Gas turbine engines typically include a compressor, a combustor, and a turbine. The compressor compresses air drawn into the engine and delivers high pressure air to the combustor. In the combustor, fuel is mixed with the high pressure air and is ignited. Products of the combustion reaction in the combustor are directed into the turbine where work is extracted to drive the compressor and, sometimes, an output shaft. Left-over products of the combustion are exhausted out of the turbine and may provide thrust in some applications.
Products of the combustion reaction directed into the turbine flow over airfoils included in stationary vanes and rotating blades of the turbine. The interaction of combustion products with the airfoils heats the airfoils to temperatures that may require the airfoils to be actively cooled by supplying relatively cool air to the vanes and blades. Relatively cool air may sometimes be passed through the airfoils of the vanes and blades to allow those components to withstand the high temperatures of the combustion products. Cooling airfoils of the vanes and blades to withstand those temperatures remains an area of interest.